Thermal turbomachines such as gas turbines or jet engines have long been known. In these machines, a fluid is generated from combustion gases, with the aid of fuel combustion, this fluid driving rotors to rotation for the purpose of thereby generating energy or propulsion. The combustion gases in the flow channel usually have very high temperatures, so that lining elements, heat protection panels and/or cooling channels as well as insulating elements are provided between the flow channel and the housing of the turbomachine for the purpose of adjusting a steep temperature gradient from the flow channel to the housing.
Furthermore, the shell radially surrounding the flow channel must also ensure that fluid can possibly not escape from the flow channel, so that, if possible, all the combustion gases are available for driving the rotors. In certain circumstances, however, this is difficult to accomplish, due to the complex structure of the shell, including the housing, heat protection panels, lining elements and components for cooling air channels, since many different components must be connected to each other. As a result, gaps and cavities may easily form, through which both fluid may escape from the flow channel and cooling air may penetrate the flow channel. For this reason, it is important when designing the shell around the flow channel to make sure that sealing surfaces are provided between the individual components, which avoid leaks with regard to the flow channel.
A casing ring for a turbomachine, as illustrated in FIG. 1, is known from DE 101 22 464 C1. The turbomachine illustrated in FIG. 1 has a moving blade ring 11 which includes a shroud having two seal tips 13, 14, which interact with a run-in coating 6 in a honeycomb structure. Stationary blades 15, 16 are apparent upstream and downstream from moving blade ring 11, which are statically situated in housing 17 of the turbine as individual parts or as segments composed of multiple blades.
The radially outer end of stationary blade 15 is located in a groove 18 of housing 17 which is radially open to the inside and runs around housing 17. The radially outer end of stationary blade 16 engages with a groove 19 of housing 17 which is axially open to the rear and runs around housing 17, the area surrounding groove 19 also being referred to as the housing hook. Stationary blade 15 (on the left, outside the illustration) also has a comparable suspension. Casing ring 1 extends axially from stationary blade 15 to stationary blade 16 as well as around housing 17 in the circumferential direction. The casing ring has a segmented design. A seal carrier 3, which holds run-in coating 6 as part of the outer air seal (OAS), is situated on the hot gas side.
A securing element 7 is provided on the housing side, whose primary function is to secure stationary blade 15 against being released from groove 18. In addition to run-in coating 6, seal carrier 3 also includes a shell-like carrier part 4 and a stop part 5. Multiple seal carriers 3 of this type are positioned adjacent to each other over the circumference of the machine. Securing element 7 includes a C-shaped securing part 8 in the axial sectional view, which grips groove 18 with the aid of the stationary blade end, a shell-type shielding section 9 and a stop part 10, which resembles a hook in the axial cross-sectional view. Elements 3 and 7, which are spaced as far apart as possible, have defined contact points C1, C2 whose extension is minimized with regard to minimal heat conduction, e.g., with the aid of periodic interruptions in the circumferential direction, which, however, are necessary for mutual support.
The illustrated configuration is problematic in that the sealing effect of stop part 5 decreases during operation, and gaps are able to form between stop part 5 and housing hook 19, which may result in the loss of flowing fluid.